Computer-assisted method development is now well established in high performance liquid chromatography (HPLC). One widely used approach (DryLab G, LC Resources) optimizes gradient elution methods on the basis of two experimental runs (different gradient times). Subsequent computer simulation is used to explore the effects of variables such as: initial and final %-strong solvent (%-B), gradient time, gradient shape (including segmented gradients), column dimensions, particle size and flowrate. Computer simulation provides the equivalent of a large number of experimental runs in a very short time. It is proposed to develop similar software for optimizing temperature programmed (or isothermal) gas chromatography (GC) methods. Literature reports suggest that considerable control over band- spacing and resolution is possible through the use of segmented temperature programs. This phenomenon has not been widely exploited because of the large number of experimental runs required to identify the optimum conditions. The development of a practical computer-assisted optimization program for GC should result in significant savings in method development time for analysis of complex samples such as drug metabolites in biological fluids, and allow easy modification of existing methods to adapt them more closely to the needs of specific analyses.